Wrapping method and apparatus

ABSTRACT

A wrapping method comprising the steps of heating strings at one opening of a tubular net made of thermoplastic synthetic resin strings to join the strings together and fitting the resulting tubular net having joined strings over an article to be wrapped. An apparatus for practicing the method is also disclosed.

United States Patent 1 Kobayashi et al.

[451 Oct. 8, 1974 WRAPPING METHOD AND APPARATUS [76] Inventors: Mikio Kobayashi, 569 Osaka-fu,

Takatsuki-shi, Nishi-machi 25-ban 12-g0, Takatsuki; Masao Asada, 573 Osaka-fu, Hirakata-shi, Nakamiyakita-machi 2-ban l-go, Hirakata; Shohei Kawasaki, 601 Kyoto-fu, Kyoto-shi, Minami-ku, Kisshoin Hattanda-cho 8-banchi, all of Kyoto, Japan 22 Filed: Dec. 27, 1972 [21] Appl. No.: 319,036

[30] Foreign Application Priority Data Dec. 29, 1971 Japan 46-3688 Feb. 18, 1972 Japan 47-17534 Feb. 18, 1972 Japan 47-17535 [52] US. Cl 53/29, 53/1-79, 53/183,

[51] Int. Cl. B65b 43/08 [58] Field of Search 53/29, 179, 183, 193, 242; 156/510 X [56] References Cited UNITED STATES PATENTS 3,374,599 3/1968 Sanders 53/29 3,662,514 5/1972 Goss 53/193 X 3,728,840 4/1973 Izumi 53/29 Primary Examiner-Travis S. McGehee Attorney, Agent, or Firm-Edwin E. Greigg [57] ABSTRACT A wrapping method comprising the steps of heating v strings at one opening of a tubular net made of thermoplastic synthetic resin strings to join the strings together and fitting the resulting tubular net having joined strings over an article to be wrapped. An apparatus for practicing the method is also disclosed.

20 Claims, 25 Drawing Figures PAIENIEUBBT 8M4 3.889.842

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sum :10 or 10 WRAPPING METHOD AND APPARATUS BACKGROUND OF THE INVENTION This invention relates to a method and an apparatus for wrapping articles with tubular nets made of thermoplastic strings and made deformable as desired.

Methods heretofore proposed or adopted for wrapping articles as aforementioned are:

l. A type of method by which an article is wrapped with a tubular net having its strings at the first opening in a bundle.

2. A type of method by which an article is wrapped with a tubular net the first opening of which has been reduced diametrically through the contraction of the strings.

3. A type of method which comprises fitting a ring of a suitable diameter around a tubular net, folding a portion of the net at one side of the ring over the other side portion of the net, with the ring covered with the folded portion, and wrapping an article with the tubular net having a double layer thus formed.

The method (1) has a defect in that solid lumps are formed in the tubular net by joining the strings in a bundle and, while the wrapped articles are transported in containers, the lumpscontact with the other wrapped articles causing damages to the wrapped articles, particularly when the wrapped articles consist of fruits. Furthermore, in the case that the wrapped articles are fruits and the like, the wrapped articles are preferably displayed without removing covering tubular nets to enhance value of merchandise on display, the wrapped articles show a poor appearance because of the solid lumps, and it was impossible to place the wrapped articles with the joined strings beneath so as to improve appearance.

The types (2) and (3) of methods described above, though defect in type (1) of method is eliminated therein, have other defects as mentioned below:

In the case of the method (2), the wrapped article tends to expand the reduced opening under gravity, so that the article is liable to drop through the enlarged opening, in as much as the constituent strings have merely been contracted with the mesh structure remaining intact. Moreover, the method is not applicable to a foamed synthetic resin net which undergoes hardly any contraction.

On the other hand, the method (3) requires the ring in addition to the tubular net and it is also necessary to use a great amount of the net because of the double structure, hence costly. Furthermore, the difficulties encountered in folding over a portion of the tubular net mechanically result in low wrapping efficiency and prevent an automatic and labor-saving operation.

The present invention has been accomplished to solve all of the foregoing problems.

SUMMARY OF THE INVENTION This invention provides a wrapping method comprising the steps of retaining a tubular net made of thermoplastic synthetic resin strings in a tubular shape, gathering the strings at the edge of the first opening of the tubular net thus retained toward the longitudinal axis of the tubular net, joining the gathered strings together by heating and fitting the resulting tubular net over an article to be wrapped by inserting the article into the tubular net from its second opening. The invention also provides an apparatus for practicing this method.

Namely, since the tubular net is retained in a tubular shape joining the strings gathered at the edge of the first opening of the tubular net, no solid lump is formed in the joint portion and accordingly, there is no possibility of causing damage on the wrapped articles in the course of transportation and poor appearance on display keeping wrappers intact as result of solid lumps as aforementioned. Further, while the opening may not be optionally formed, when it is formed" at the portion where strings are joined, the diameter of the opening is suitably determined in accordance with the size and shape of the article to be wrapped so as to preclude any objection such as dropping of the article through the opening and permit the strings and the opening to keep the wrapped article in a stable position when the article is seated with the opening down.

Since the strings are joined together by heating, the method is applicable to foamed synthetic resin strings and gives a tubular net having an attractive shape.

Furthermore, the fact that the article can be wrapped with the tubular net in its single layer form simplifies the wrapping operation to assure automation, savings in labor and improved efficiency, reduces the amount of the tubular net required and eliminates the need to use some material other than the tubular net, hence economical with respect to wrapping material. Thus the invention achieves great cost reduction in the overall wrapping operation.

According to the wrapping method of this invention which involves a very simple operation, it is easy to use a long tubular net, which may be severed to a specified length in accordance with the size and shape of the article to be wrapped, followed by the foregoing wrapping operation conducted mechanically. In this way, a fullautomatic wrapping system can be provided readily.

Further, since an article is wrapped with the tubular net keeping the article intact, damage to the wrapped article to be caused by being gripped or moved, can be precluded advantageously.

The wrapping method and apparatus of this invention, being applicable to strings made of foamed synthetic resin as described above, are very suitable for wrapping an article such as apple which is very susceptible to bruise and which is therefore preferably to be displayed in wrapped state.

An object of this invention is to provide a method and an apparatus for wrapping articles with tubular netsmade of thermoplastic synthetic resin economically and efficiently.

Another object of this invention is to provide a method and an apparatus for wrapping articles with tubular nets having an opening which permits the wrapped article to be seated stably, the wrapped article further being prevented from dropping off the net through the opening.

Still another object of this invention is to provide a method and an apparatus capable of an automatic and labor-saving wrapping operation with ease.

Further another object of this invention is to provide a method and an apparatus most suitable for wrapping fruits which are susceptible to bruise.

Other'objects and advantages of this invention will become apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS means in the course of its movement from the position shown on the line Xl-XI in FIG. 1 to the position shown on the line XII-XII in FIG. 1.

FIG. 9 is a side-view taken on the line of XIIXII in FIG. 1.

FIGS. 10 and 11 are side-views of the shaping means in the course of its movement from the position shown on the line XIIIXIII in FIG. 1 to the position shown on the line XIVXIV in FIG. 1.

FIG. 12 is a side-view taken on the line of XIVXIV in FIG. 1.

FIG. 13 is a side view taken on the line of XVXV in FIG. 1.

FIG. 14 is a partially broken away side-view to show tubular net of joined strings.

FIGS. 15 through 25 show second embodiment of the apparatus.

FIG. 15 is a plan figure.

FIG. 16 is a partially broken away side-view taken on the line of VI-VI in FIG. 15.

FIG. 17 is a partially broken away abridged side-view taken on the line of VII--VII in FIG. 15.

FIG. 18 is a sectional view taken on the line of VIII- VIII in FIG. 15 showing the tubular net in a state of being heated.

FIGS. 19 through 25 are partially abridged oblique views showing process of wrapping operation, of which,

FIGS. 19 through 25 are views of the left side of the rotary body as seen from the left lower position of FIG. 15.

FIG. 23 is a view of the upside of the rotary body as seen from the left upper position of FIG. 15.

FIG. 24 is a view of the upside of the rotary body and the tubular holder as seen from the left upper position of FIG. 15.

FIG. 25 is a view of the tubular'holder and the belt conveyor as seen'from the left upper position of FIG. 15.

DESCRIPTION OF TI-IEPREFERRED EMBODIMENTS A first embodiment will be described with reference to FIGS. 1 to 14. A rotary cylinder 1 has a center shaft 11 supported on a table 12. Drive means 13 intermittently drives the rotary cylinder 1 a definite angle at a time. A frame 14 is mounted on the table 12.A stationary shaft 15 fixed to the frame 14 is coaxial withthe rotary cylinder 1 and rotatably supports the upper and lower ends of the rotary cylinder 1. The shaft 15 thus permits the rotary cylinder 1 to rotate stably and is provided with cams to be described later.

An outer cylindrical die 2 has an inner diameter nearly equal to the outer diameter of a tubular net 9 made of strings of thermoplastic synthetic resin. The lower end of the die somewhat flares outward. A plurality of brackets 23 are fixed to the outer peripheral surface of the rotary cylinder 1 at nearly equal spacing in its circumferential direction. Each of the brackets 23 has two parallel guide rods 22 extending radially of the rotary cylinder 1 and having a stopper 24 at the distal ends thereof. Each pair of the guide rods 22 carries a holder 21 which is slidable thereon so that the outer cylindrical die 2 on the holder 21 is movable radially of the rotary cylinder 1. A plate cam 25 is secured to the stationary shaft 15. A link rod 26 is fixedly supported on the rotary cylinder 1. When the rotary cylinder I rotates, the plate cam 25 permits an end of the link rod 26 to move radially of the rotary cylinder 1, whereby the holder 21 and the outer cylindrical die 2 are moved radially of the cylinder 1. The link rod 26 is urged by a spring 27 toward the axis of the rotary cylinder 1 all the time.

A core member 3 comprises a cylinder having a truncated conical head and serves to form, between the inner peripheral wall of the outer die 2 and the outer peripheral wall of the core member 3, an annular space for retaining the tubular net 9. The core member 3 is detachably mounted on a guide rod 31 which extends through .a bearing 32 fixed to the outer peripheral surface of the rotary cylinder 1, the guide rod 31 being movable upward and downward. A position adjusting member 33 in the form of a disc having a diameter greater than the outer diameter of the core member 3 is mounted on the guide rod 31 below the core member 3 and controls the position of the tubular net 9 relative to the core member 3 when it is located between the outer die 2 and the core member 3. Indicated at 34 is a groove cam secured to the stationary shaft 15, at 35 a link rod supported on the inner face of the rotary cylinder 1. The rotation of the rotary cylinder 1 causes the groove cam 34 to move the link rod 35 up and down aboutits support point, whereby the guide rod 31 and the core member 3 thereon, are also moved up and down. The outer cylindrical die 2 and core member 3 constitute first means for holding the tubular net in a tubular form. The first means may be of various modified constructions. The tubular net 9 retained on the first means is such that at least the strings at the edge of its first opening project from the annular space to an almost definite level.

A member 4 for heating the strings has a cavity in the form of a truncated cone resembling the head of the core member 3. The cavity is positioned in an opposing relation to the head of the core member 3. Indicated at 41 is a bracket, at 42 a heater, at 43 a cam rod, at 44 a cam rod guide, at 45 a spring for pushing up the cam rod, at 46 a cushioning spring, and at 47 a cam fixed to the frame 14. The bracket 41 which is secured to the upper end of outer peripheral face of the rotary cylinder 1 supports the cam rod guide 44 and heater 42 coaxially with the core member 3. The cam rod guide 44 receives the cam rod 43 in upwardly and downwardly movable manner. The rotation of the rotary cylinder 1 moves the. cam rod 43 up and down by means of the cam 47 and spring 45. The spring 45 urges the cam rod 43 upward toward the cam 47 all the time. The member 4 is fixed to an end of the cam rod 43 and is movable up and down to contact the heater 42 or engage with the core member 3. Thus the member 4 is heated by the heater 42 when it is away from the strings. The member 4 and heater 42 constitute third means to be pressed against the strings at the edge of first opening of. the tubular net 9 which are gathered closely so as to join the strings together by heating and to thereby render the first opening almost free of variation in its diameter. The temperature of the member 4 may be such that the strings of the tubular net 9 will be joined together with sufficient strength. The temperature may be about 130 to I80C for instance, in the case of a foamed tubular net made of polyethylene resin. If the temperature given by the member 4 is excessively high the strings will be melted into a thin film, hence objectionable. It is desired that the member 4 be made of an about 1.5mm thick aluminum, copper or like plate having good heat conductivity, inasmuch as heating and cooling are preferably effected rapidly. To render the fused strings readily releasable from the die, it is advantageous to coat the member 4 with Teflon. If the heat capacity of the member 4 is set at a minimum level re-- quired to join the strings of approximately one tubular net 9, excessive melting of the strings can be avoided to assure high strength at the junction.

A gathering plate 5 constitutes second means for gathering the strings at the edge of first opening of the tubular net 9 toward the head of the core member 3, namely toward the vertical axis of the tubular net 9 retained in position so as to form a constricted shape. The gathering plate 5 is formed with an annular hole having a taper approximately the same as the slope of head of the core member 3 and a minimum diameter almost equal to the outer diameter of the core member 3. It is positioned immediately below the member '4 coaxially therewith and is movable up and down like the member 4. A bracket 51 is integral with the bracket 41. Guide rods are indicated at 52 and springs at 53. Two guide rods 52 extend vertically from the bracket 51 in parallel. The gathering plate 5 is guided by the rods 52 for upward and downward movement. Pins 54 are provided on the side faces of the gathering plate 5. A cylindrical cam 55 is fixed to the stationary shaft 15. A link rod-56, supported on a fixed support on the inner surface of the rotary cylinder 1, is pivotally moved up and down about the support point by means of the cylindrical cam 55 as the rotary cylinder 1 rotates, with the result that an end of link rod 56 moves the pins 54 up and down. Springs 53 always urge the gathering plate 5 toward the link rod 56 with the pins 54 in pressing contact with the end of the rod 56. The outer cylindrical die 2, core member 3, member 4 and gathering plate 5 constitute a set of shaping means. Twelve sets of such shaping means are provided along the outer peripheral face of the rotary cylinder 1 at equal spacing. Each set of shaping means stops at the respective position indicated in FIG. 1 and then moves in the direction of arrow. The outer cylindrical die 2 changes its position as shown in FIG. 1 as the shaping means moves.

Fifth means 6 for supplying to the first means the long tubular net 9 which is folded to a flat shape and rolled up inserts the net 9 into the outer die 2 at the position shown in FIG. 5 from the lower end thereof. The fifth means 6 is provided with sixth means comprising two pairs of pinch rolls 61 and 62 and a cutter 63. The pairs of pinch rolls 61 and 62 are spaced apart from each other along the linear feed path of the long tubular net 9, with axes of rolls of one pair positioned substantially at right angles with those of rolls of the other pair, the axes of pairs of rolls 61 and 62 further being approximately at right angles with respect to the feed path. A roll of the tubular net is indicated at 64 and a stand at 65. The long tubular net 9 folded in a flat shape is paid out from the roll 64 by the pair of pinch rolls 62, and through the action of both pairs of rolls 61 and 62 the first folds of the folded net are brought to a position approximately at the middle of its width. The folded net is further folded to form second folds substantially in parallel to the first folds at a different position. In this invention, the word fold is to be construed as a bending line of the tubular net when it is bended and does not necessarily indicate that creases are left on tubular net. Thus formed with the second folds, the flattened net will be shaped into a tubular form at a suitable position beyond the pair of rolls 62. The tubular net is then inserted into the outer cylindrical die 2 a suitable length and severed by the cutter 63. In this way, the long tubular net is cut into pieces having a nearly uniform length in its axial direction. A plurality of guide rolls are provided between the pinch rolls 61 and 62 to. assure that the folded net will be unfolded smoothly. Further, a ball may be placed in the tubular net positioned between both pairs of rolls 61 and 62 to give an advantage of an exact unfolding of the tubular net. The ball as light in weight as possible in suitable size is selectively used.

A presser 7 having a spherical upper surface is pro vided below the outer cylindrical die 2 at the position shown FIG. 12. The strings along the edge of second opening of the tubular net 9 retained on the outer cylindrical die 2 are pressed by the presser 7 against the conical face of flaring portion of the outer die 2, whereby the second opening is forced radially outward to an increased diameter. An air cylinder 71 pushes the presser 7 against the outer die 2 and retracts the same away therefrom. The pressure 7 and air cylinder 71 constitute means for increasing the diameter of second opening of the tubular net.

A pusher 8 is disposedabove the outer die 2 at the position shown in FIG. 13. The tubular net 9 which is retained on the outer die 2, with the strings at its first opening joined together and those at its second opening forced outward, is pushed out from the outer die 2 in the direction toward the second opening by the pusher 8. An air cylinder 81 forces the pusher 8 upward and downward. A conveyor belt 82 is provided with stands 83 positioned at equal spacing. Indicated at 84 are apples which are the articles to be wrapped. The conveyor belt 82 is driven intermittently in synchronism with the intermittent rotation of the rotary cylinder 1 in such manner that the stand 83 stops beneath the outer cylinder die 2. The stand 83 is formed in its top with a recess for seating the article 84 to be wrapped in stable fashion. The pusher 8, air cylinder 81, belt conveyor 82 and stands 83 constitute fourth means for placing the tubular net 9, pushed out from the die 2, over the article 84.

Apples are wrapped in the following manner on the apparatus described.

The outer cylindrical die 2 in the position shown in FIG. 5 is located on the outer path. The long tubular net 9paid out upward by the pair of pinch rolls 62 is shaped into a cylindricalform by the pairs of pinch rolls 61 and 62 and then inserted into the outer die 2. When a predetermined length of the tubular not has been inserted into the outer die 2, the pairs of rolls 61 are stopped automatically, whereupon the cutter 63 is actuated to cut off the net. In this position, the core mem ber 3 is in its depressed position, while the member 4 and gathering plate 5 is in an elevated position. The member 4 is kept heated by the heater 42 in contact therewith. Being kept flattened for a long period of time, the tubular net 9 tends to restore the original shape even within the outer cylindrical die 2. Since the restoring force serves to hold the tubular net 9 to the inner wall of the outer die 2, the net 9 will not drop even if the inner diameter of the outer die 2 does not coincide with the outer diameter of the net 9. Preferably, the outer cylindrical die 2 may be so tapered in its interior that the inner diameter at its upper portion is somewhat smaller than the outer diameter of the tubular net 9 and the inner diameter at its lower portion is slightly greater than the outer diameter of the tubular net 9 so as to assure that the tubular net 9 will be retained within the outer die 2.

The rotary cylinder 1 is intermittently rotated by the drive means 13 from the position shown in FIG. 5 to the position shown in FIG. 9 in operative relation to the cutter 63. The first half of the rotation causes the plate cam and spring 27 to move the link rod 26 inwardly of the rotary cylinder 1, pivotally about the support point, causing the holder 21 of the outer die 2 as shown in FIG. 6 to slide on the guide rods 22 to bring the outer die 2 to the inner path, where it is retained coaxially with the core member 3 and heating member 4. Subsequently, the latter half of the rotation causes the cam 34 to move the distal end of the link rod 35 upward to push up the guide rod 31, with the resultthat the core member 3 on the end of the guide rod 31 is inserted into the cylindrical outer die as shown in FIG. 7, with the tubular net 9 in the outer die 2 retained between the core member 3 and the outer die 2. The position of the core member 3 inserted in the outer die 2 is so adjusted by the cylindrical cam 34 that the top of the core member 3 will project slightly from the upper end of the outer die 2. When the core member 3 moves upward, the position adjusting member 33 on the guide rod 31 also rises to cause the upper end of the tubular net 9 to project upward from the head of the core member 3 a substantially definite amount. Simultaneously with the insertion of the core member 3 into the outer cylindrical die 2, the cylindrical cam 55 moves the front end of the link rod 56 pivotally downward, permitting the spring 53 as shown in FIG. 8 to depress the gathering plate 5 toward the core member 3, so that the upper end of the tubular net 9 is gathered onto the head of the core member 3. A little after the depression of the gathering plate 5, the cam 47 depresses the cam rod 43 through the spring 46 so that the gathered strings as shown in FIG. .9 are pressed between the core member 3 and the heating member 4 on the cam rod 43. Since the tubular net 9 has previously been gathered toward the head of the core member, the heating member 4 having a truncated conical cavity, when pressed against the head of the core member 3, causes the strings of the net 9 to gather more closely over the head of the core member 3. Since the heating member 4 has been heated by the heater 42 in contact therewith, the

strings of the net 9 closely gathered together are heated and pressed between the core member 3 and the heating member 4, with the result that the adjacent strings are joined together. The position of the heating member 4 relative to the core member 3 is so controlled as to provide a clearance therebetween and thereby pre' vent the strings, especially foamed plastic strings, from being collapsed. Accordingly, the strings will be fused and joined together only at one side face thereof which is in contact with the heating member 4. The foamed strings will therefore retain cushioning properties. To provide the clearance between the heating member 4 and core member 3, a stopper may be disposed at the top of the head of the core member 3 or at the center of the cavity of the heating member 4. Particularly if the stopper is in the form of a disc or a ring which is positioned concentrically with the core member 3 and the heating member 4, the first opening formed by the joined strings of the net 9 will be precisely circular and attractive in appearance. The apple can then be seated stably when placed with the opening down.

While maintaining the state shown in FIG. 9, the strings of the tubular net 9 heated and pressed between the core member 3 and the heating member 4 are cooled and integrally joined together, thereby turning the tubular net 9 into the state shown in FIG. 14. The heating member 4 may be cooled spontaneously, or cooling air or mist may be applied to the heating member 4 for rapid cooling.

During the first half of rotation of the shaping means from the position taken on the line XIIIXIII in FIG. 1 to the position shown in FIG. 12, the as seen in FIG. 10 heating member 4 is raised by the spring and the gathering plate 5 is pushed up by the cylindrical cam to move away from the core member 3, which in turn is depressed by the groove cam 34 away from the outer cylindrical die 2. The heating member 4 separated from the core member 3 comes into contact with the heater 42 and is heated again. If the heating member 4 is controlled to start retraction from the core member 3 slightly earlier than the raising of the gathering plate 5, the heating member 4 will be separated from the junction of the tubular net 9 while it is held by the gathering plate 5. Consequently, the joined portion of the tubular net 9 will be prevented from moving up with the heating member 4.

During the latter half of rotation of the shaping means, as shown in FIG. 11, the cam 25 pushes the outer cylindrical die 2 from the inner path to the outer path. The presser 7 is pushed upward by the air cylinder 71 toward the outer cylindrical die 2 at the position shown in FIG. 12. The strings along the edge of second opening of the tubular net 9 held in the outer die 2 are therefore pressed by the presser 7 against the flaring portion at the lower end of the die 2 so as to expand the second opening of the net 9 outward. This assuresthat the tubular net 9 can be smoothly placed over an article to be wrapped such as an apple.

When the shaping means is brought to the position shown in FIG. 13 through further rotation of the cylinder 1, the outer die 2 is positioned immediately above the apple 84 on the stand 83 on the conveyor belt 82. The tubular net 9 retained in the outer die 2 is pushed from above downward toward its second opening by the pusher 8 which is operated by the air cylinder 81. Since the tubular net 9 is made of foamed strings and retained in a tubular shape within the outer die 2, the tubular net 9 can be placed over the apple 84 and stand 83 smoothly simply by being pushed down.

When the pusher 8 is withdrawn, the conveyor belt 82 is driven to ring the next apple to the position directly below the outer die 2 at the position shown in FIG. 13 in preparation for the next wrapping operation. The apple. 84 thus wrapped is sent from the end of the conveyor belt to a storage by way of a chute. When the apple 84 leaves the stand 83, the tubular net 9 covering the side face of the stand 83 contracts diametrically to serve as a good wrapper covering the peripheral surface of the apple 84. The outer cylindrical die 2 further rotates along the outer path to return to the position shown in FIG. 5. In this way, the foregoing operation will be repeated automatically.

While the foregoing description is given with respect to only one set of shaping means, the other sets of shaping means also operate in the same manner as above.

Although the apples are continuously wrapped by the foregoing apparatus, the tubular nets 9 alternatively be taken out at the position shown in FIG. l2 and then placed over the articles 84 in another process. Further at least one set of the shaping means may be provided. In the case where the apparatus includes one set of the shaping means, for instance, the heating member 4, gathering plate 5, outer cylindrical die 2 and core member 3 may be provided coaxially in such order of arrangement, and the core member 3 may be inserted into or retracted from the outer die 2 by an air cylinder, with the gathering plate and heating member 4 adapted to be pressed against or retracted from the outer die 2.

Although the illustrated embodiment includes the gathering plate 5 as the second means, the gathering plate 5 is not always necessary. For instance, if the head of the core member 3 and the cavity of the heating member 4 are in the form of a truncated cone or sphere, they can serve as the second means. Further if the gathering plate 5 is used, the head of the core member 3 and the heating member 4 may be plane.

The strings may be made of polyethylene, polypropylene, polyvinyl chloride, polystyrene, or the like. Ei-

ther of foamed synthetic resin or nonfoamed synthetic resin is employable, and the former is very suitable for wrapping especially fruits which are easily bruised. In the case where a foamed material is used, the foamed string may preferably have a diameter of 4 to 10 mm and a foaming degree of about 10 to times. The diameter of the tubular net may be determined suitably depending upon the size of the fruit to be wrapped. For instance, a tubular net measuring mm in inner diameter and 5 mm in the diameter of strings which form rhombic meshes measuring about 20 to 25 mm in diagonal line longitudinally of the tubular net and about 7 to 10 mm in diagonal line circumferentially thereof can be used satisfactorily for wrapping fruits having an outer diameter of up to about 100 mm simply by adjusting the length of the tubular net. Further in the case of a tubular net made of a foamed material, the material may preferably be closed-cellular having some resillCl'lC With reference to FIGS. 15 to 25, a second embodiment will be described. This embodiment comprises a rotary body 101 having a square form in plan and provided with four sets of shaping means along each of its four sides, namely 16 sets in total, each of the shaping means having a vertical center axis. The apparatus wraps up four articles at the same time.

The rotary body 101 is in the form of rectangular parallelepiped having a square shape in plan. A rotary shaft 102 is positioned at its center and extends vertically through its lower end. The rotary shaft 102 is supported on a frame 103 by a bearing and driven intermittently through at a time by intermittent driving means 104 disposed within the frame 103. The driving means 104 may have a construction of the known type such as Geneva mechanism, drum cam mechanism, indexing mechanism or the like and either one of mechanism is optionally adoptable. The rotary body 101 is provided with four sets of shaping means along each of its four sides, i.e., 16 sets of such means in total..'

Each set of the shaping means comprises an outer cylindrical die 105, a core member 106 and a heating member 107 arranged on the same vertical axis. The same parts of the four sets of shaping means at one side of the rotary body 101 are equidistantly spaced apart and mounted together in parallel to the side. They are movable in the vertical direction. The outer cylinder die 105 and a core member 106 constitute first means for'keeping the tubular net in tubular shape.

Each bracket 109, secured to the side of the rotary body 101 carries a heater 110. The heating member 107 is mounted on the lower end of a guide rod 111 passing through the center of the heating 110 and adapted to contact the heater 110 when the guide rod 111 move up. Slide bearings 112 are mounted on the opposite ends of the bracket 109. This construction constitutes third means for heating the strings at the edge of first opening of the tubular net 108 and joining the strings.

The outer cylindrical dies 105 positioned below the heating members 107 are mounted on the holder plate 113, whose opposite ends are provided with bearing 114 fixedly carrying guide rods 115. The guide rods 115 fit in the slide bearings 112 for upward and downward sliding movement. The upper ends of the guide rods 115 are supported on a guide plate 116, the arrangement being such that the upward and downward movement of the guide plate 116 causes the guide rods 115, holder plate 113 and outer cylindrical dies 105 to move upxand down together. Stoppers 200 determine the lower limit of movement of the holder plate 113. The guide plate 116 is moved up and down by an air cylinder 117 supported on a bracket fixed to the upper end of side face of the frame 101. Also supported on the guide plate 116 are the guide rods 11] for the heating members 107. The upward and downward movement of the guide plate 1 16 causes the outer cylindrical dies 105 and the heating member 107 to move up and down at the same time. The guide rods 115 and 111 supported on the guide plate 116 carry compression springs 118 and 119 respectively acting therebetween. When the descending guide rods 115 brings the holder plate 113 into contact with the stoppers 200, the compression springs 118 permit the guide plate 116 to move further downward along the guide rods 115 while the compression springs 118 are compressed by the guide plate 116. The compression springs 119 serve to absorb impact when the heating members 107 come into contact with the top faces of the core members 106 positioned under the heating members 107. The compression spring 118 has a compressed length which is greater than the distance of depression of the guide plate 116 after the older plate 113 strikes the stoppers 200 until the heating members 107 strike the core members 106.

The core members 106 are fixed at their bottoms to a pivotal plate 120 positioned below the outer dies 105. The pivotal plate 120 is provided at its opposite ends with pins 121 which are supported on bearings 122. A motor 123 pneumatically moves the pivotal plate 120 a given angle pivotally about the pins 121. By virtue of the pivotal movement of the pivotal plate 120, the core members 106 are inclined in such direction that the upper ends thereof are moved from the vertical position away from the side face of the rotary body 101. A stopper 124 limits the angle of pivotal movement of the pins 121.

A position adjusting member 125 regulates the position of lower end of the tubular nets 108 placed over the core members 106 so as to position the nets 108 substantially in uniform relation to the core members 106. The member 125 also serves to remove the tubular nets 108 from the core members 106 when pushed up. The position adjusting member 125 fits around the core members 106 loosely in parallel to the pivotal plate 120 and is connected to an air cylinder 126 fixed to the pivotal plate 120. Through the action of the air cylinder 126, the position adjusting member 125 moves up and down along the core members 106. Guide rods 127 assure that the position adjusting member 125 moves in parallel to the core members 106. Stoppers 128 determine the limit of downward movement of the position adjusting member 125.

129 constitutes fifth means by which the long tubular net 108 folded flat and rolled up is fed to the first means. The tubular net 108 is placed from above over each of the four core members 106. The fifth means 129 has a guide rod 130, two pairs of pinch rolls 131 and 132 a cylindrical guide 134 and a cutter 135. The pair of pinch rolls 131 is positioned at right angles to the axis of the guide rod 130, while the pair of pinch rolls 132 is located in parallel to the guide rod 130, one of the rolls being driven in such direction as to send the tubular net 108 downward. The cylindrical guide 134 guides the tubular net 108 downward while maintaining nearly cylindrical sectional form of the net. The flattened long tubular net 108 is passed over the guide rod 130 and turned 90 and guided through the nip of the pair of rolls 131. Through the action of the pairs of pinch rolls 131 and 132, the net 108 is folded again so as to position the first folds thereof to the approximate middle of its width, thereby forming second folds at a position different from that of the first folds but in parallel to the first folds. After passing between the pair of pinch rolls 132, the flattened net 108 is restored to a tubular shape and passed through the cylindrical guide 134 to assume a substantially cylindrical shape. The net is then placed over the core member 106. When the net in a predetermined length has been fitted over the core member 106, feeding of the net 108 is interrupted, whereupon that length of the tubular net 108 is cut off by the cutter 135 between the cylindrical guide 134 and the core member 106. When inclined, the core member 106 is in alignment with the linear path of transport of the tubular net 108 extending through the nips of the pinch rolls 131 and 132 and the cylindrical guide 134.

A tubular holder 136 has an inner diameter nearly equal to the outer diameter of the tubular net 108. By virtue of elevation of the position adjusting member 125, the tubular holder 136 receives the net 108 from the core member 106 and holds the same.

Four tubular holders 136 are mounted on a frame 137. The frame 137 is provided at its upper opposite portions with pins 138 by which the frame 137 is supported on bearings 139 on a frame 140. A motor 141 mounted on the frame 140 pivotally moves the pins 138 through a given angle, whereby the tubular holders 136 are moved pivotally reciprocally between position in coaxial direction of the inclined core members 106 and vertical position.

A pusher 142 is supported within the tubular holder 136 to push down the tubular net 108 retained within the holder 136 onto an article 143 to be wrapped. The pushers 142 are connected by rods 145 to a beam 144 which is slidable along duide grooves in the opposing inner side faces of the frame 137. The beam 144 is con nected to an air cylinder 146 mounted at the midportion of upper end of the frame 137. The air cylinder 146 operates to move the beam up and down. Indicated at 147 is a conveyor belt carrying thereon stands 148 at a predetermined spacing. Apples, illustrated as the articles 143 to be wrapped, are placed on the stands. The stands 148 are spaced apart so as to position immediately below the tubular holders 136 when the holders are oriented in the vertical direction.

According to this embodiment, the intermittent rotation of the rotary body 101, operation of the shaping means, supply of the tubular nets 108 and wrapping operation are controlled by limit switches and timers to effect operations automatically in succession.

The apparatus described operates in the following manner to wrap up apples one after another with a cushioning material, i.e., tubular foamed polyethylene nets 108.;

The core members 106 are inclined by the motor 123 in the position corresponding to fifth means 129 as shown in FIG. 19. Through the rotation of the pair of pinch rolls 132, a predetermined length of each net 108 is paid out and fitted over the core member 106 and cut off by the cutter 135. Thus covered with the tubular nets 108, the core members 106 are pivotally moved again to the vertical position as seen in FIG. 20. Subsequently, the air cylinder 117 operates to push down the guide plate 116, which in turn lowers the guide rods 115 and 111, causing the outer cylindrical dies and the heating members 107 to move downward toward the core members 106 resulting in the state shown in FIG. 21 At this time, the stoppers 200 determine the position to which the outer dies 105 descend and at which the dies 105 fit over the core members 106 with the tubular nets 108 held therebetween. The guide plate 116 further moves down to the position of FIG. 22 to press the heating members 107 against the core members 106. When the state of FIG. 20 changes to that of FIG. 21 with no movement of the guide rods 115, only the guide rods 111 move down. After the guide rods are pushed down onto the stoppers 200, the guide plate 116 compresses the springs 118 on the guide rods 115 to push down the guide rods 111 only.

When pressed against the core members 106 each of the heating members 107 gathers the upper end of the tubular net 108 in the clearance between the member 107 and the core member 106 and unites by heating the strings at the edge of first opening of the tubular net 108. FIG. 18 shows this operation of an enlarged scale.

With reference to FIG. 18, the outer cylindrical die 105 has an upper portion with reduced diameter so as to gather the upper end of the tubular net 108 toward the head of the core member 106 when it is fitted over the core member 106. The outer die 105 serves as the outer cylindrical die 2 and also as the gathering plate 5 in the first embodiment. The core member 106 has in its interior a stopper 149. The heating member 107 is fixed by a fastening member 151 to the end of the guide rod 111 with an insulating material 150 interposed therebetween. When the heating member 107 moves down, the tip of the fastening member 151 strikes against the stopper 149 to prevent the heating member 107 from direct contact with the core member 106. A lock nut for adjusting the height of the stopper 149 is indicated. The core member 106 is formed at its top end with a circular projection 153 which forms a circular hole at the gathered end of the tubular net 108. While retaining the parts in this state, the rotary body 101 rotates intermittently in the direction of arrow shown in FIG. 15. During this rotation, the top ends of the tubular nets 108 are fused between the core members 106 and heating members 107, and the heating members 107 are then cooled by application of cooling air or mist.

When rotary body 101 is brought to a halt at the position corresponding to the tubular holder 136, the air cylinder 117 operates to raise the heating members 107 and outer cylindrical dies 105 as shown in FIG. 23. The heating members 107 will then be heated by the heater 110 in contact therewith. The tubular nets 108 having strings joined together at the edge of first opening thereof are retained on the core members 106. This can be assured by making the outer diameter of the core member 106 somewhat greater than the inner diameter of the tubular net 108. The core members 106 are then inclined by the motor 123. At this time, the tubular holders 136 are coaxial with the inclined core members 106. In this state, the air cylinder 126 operates to push up the position adjusting member 125 to transfer the tubular nets 108 on the core members 106 into the tubular holders 136 resulting in the state shown in FIG. 24. After elevation, the position adjusting member 125 is moved down immediately. The core members 106 return to the vertical position under the action of the motor 123.

The tubular holders 136 are brought to the vertical position by the motor 141. Immediately below the tubular holders 136 apples 143 are provided upside down on the stands 148 on the conveyor belt. 147. By the operation of the air cylinders 146, the pushers 142 are moved downward through the tubular holders 136 to push down the tubular nets 108 toward the apples 143. Since the tubular nets 108 have been retained in the cylindrical shape, they are diametrically expanded upon contact with the apples 143 and fitted over the apples 143, whereupon the pushers 142 rise. Subsequently, the motor 141 operates to pivotally incline the tubular holders 136 in preparation for the next operation. The wrapped apples 143 drop into a carton box as the conveyor 147 travels forward. At the same time, apples to be wrapped next will be brought to the specified position.

The rotary body 101 .then rotates, followed by the supply of the tubular nets 108 at the position corre--.

sponding to fifth means 129 again to repeat the operation described.

Although the foregoing description has been given with respect to one set of shaping means, the four sets of the shaping means provided at each side of the rotary body 101 operate at the same time. Other sets of shaping means disposed at the other sides also operate in like manner. More specifically, when the rotary body 101 is brought to a halt during the intermittent rotation, the tubular nets 108 are always supplied to the core members 106 at the position corresponding to fifth means 129 and, the tubular net 108 at the position corresponding to the tubular holders 136 are transferred to the tubular holders 136 and fitted over the articles to be wrapped, and between the aforementioned two positions, the tubular nets 108 are maintained in fused state at their top ends. One turn of rotation of the rotary body 101 gives 16 wrapped apples each covered with the tubular net 108.

While this embodiment includes four sets of shaping means at each side of the rotarybody 101, a greater number of sets of the shaping means may be provided to step up the wrapping efficiency. Although the rotary body 101 used has a square shape in plan,a rotary body in the form of an equilateral polygon may be employed.

when the rotary body 101 is driven at a low speed, this serving to eliminate troubles which would otherwise take place during the intermittent rotation of the rotary body 101.

What we claim is: 1. A wrapping apparatus comprising: first means for retaining a tubular net made of thermoplastic synthetic resin strings in a tubular shape,

second means for gathering the strings at the edge of a first opening of the tubular net retained on the first means toward the longitudinal axis of the tubular net,

third means for joining together the strings gathered by the second means by heating, and

fourth means for fitting the resulting tubular net over an article to be wrapped from its second opening.

2. The apparatus as setforth in claim 1 further comprising fifth .means for feeding an elongated flatly folded rolled-up tubular net to the first means, a cutter means for severing the long tubular net approximately at definite spacing longitudinally thereof.

3. The apparatus as set forth in claim 2 further comprising sixth means for forming second folds in the long tubular net at a position different from that of its first folds but in parallel to the first folds so as to shape the net into a tubular form.

4. The apparatus as set forth in claim 3 wherein the sixth means comprises two pairs of pinch rolls spaced apart from each other along a linear path for feeding the long tubular net, the axes of one pair of the pinch rolls being approximatelyat right angles with the axes of the other pair of the pinch rolls, the axes of the pairs of pinch rolls being approximately at right angles with the linear feeding path.

5. The apparatus as set forth in claim 4 further comprising a ball positioned in the long tubular net at the position between the pairs of pinch rolls.

6. The apparatus as set forth in claim 1 wherein the first means comprises a cylinder and a core member to be inserted into and retracted from the inner space of the cylinder, the cylinder provides an internal annular space around the core member when the core member is inserted therein, the annular space being in a breadth approximately equal to the thickness of the strings, and the tubular net when positioned in the annular space is held by the cylinder and the core member, with at least the strings at the edge of the first opening of the tubular net projecting outward from the annular space.

7. The apparatus as set forth in claim 6 wherein after the core member is retracted from the inner space of the cylinder, the tubular net remain on the core member.

8. The apparatus as set forth in claim 6 wherein after the core member is retracted from the inner space of the cylinder, the tubular net remain in the cylinder.

9. The apparatus as set forth in claim 6 wherein the core member has a conical portion permitting the strings to project outward thereover and tapered toward its top having a planar top face, the second means presses the projecting strings against the conical portion of the core member to gather the same, and the third means has a heating face to be pressed against the conical face and the planar top face of the conical portion.

10. The apparatus as set forth in claim 9 wherein the operation to sever the folded long tubular net approximately at definite spacing and to cause the cylinder and the core member to retain the severed tubular net, the operation to gather the strings at the edge of first opening of the retained tubular net and to join the strings together and the operation to push out the tubular set having the joined strings from the cylinder and to fit the same over the article to be wrapped is automatically conducted as a plurality of sets of the cylinders and the core members arranged along a path of recyclic travel is drawn intermittently along the path.

11. The apparatus as set forth in claim 10 wherein the plurality of sets of the cylinders and the core members is driven intermittently as one group and all the sets in one group perform the same operations substantially at the same time.

12. The apparatus as set forth in claim 6 wherein the inner wall face of the cylinder is a conical surface and the outer wall face of the core member is a cylindrical surface, the internal space of the cylinder having reducing diameter toward its end from which the core member is inserted into the cylinder.

13. The apparatus as set forth in claim 6 wherein the cylinder has a conical surface flaring toward its edges proximate to the edge of second opening of the tubular net to be retained, the apparatus further comprising means for pressing the strings at the edge of second opening of the retained tubular net against the conical surface of the cylinder so as to diametrically expand the second opening, the fourth means being adapted to cause the tubular net having the strings joined at its first opening and the expanded second opening to be pushed out from the cylinder after the core member has been retracted therefrom and to be fitted over the article from the expanded second opening.

14. The apparatus as set forth in claim 6 wherein the core member is provided with a position adjusting member for causing the retained tubular net to be projected to a substantially uniform level.

15. The apparatus as set forth in claim 1 wherein the third means comprises a member for heating the strings and a heater for heating the member, the heater being adapted to heat the member when the member is away from the strings, the member having a heat capacity set at a minimum level required to join the strings of approximately one tubular net.

16. A wrapping method for wrapping at least one bulk article of give minimum diameter comprising the steps of:

a. supplying a tubular net of predetermined length, having first and second open ends and made of thermoplastic synthetic resin strips;

b. supporting said tubular net by circumscribing said tubular net on a supporting means;

c. gathering portions of said strings of the thus supported said tubular net toward a longitudinal axis of said tubular net, said portions being adjacent said first open end;

d. joining together said portions of said strings to shape a small opening defined by said joined strips, the diameter of said small opening being smaller than said minimum diameter of the bulk article.

e. removing said tubular net from the supporting means; and

f. fitting the thus modified said tubular net over the one or more bulk articles to be wrapped by passing one or more bulk articles into said tubular net via said second opening.

17. A method according to claim 16, further including as preliminary steps, the steps of supplying a long tubular net flatly folded and rolled up to a severing means, and severing said long tubular net to provide at least one said tubular net of predetermined length.

18.-A method according to claim 17, including the step of forming a plurality of folds in said long tubular net before the severing step, said folds being substantially parallel to each other.

19. A method according to claim 16, including the step of diametrically expanding said tubular net before said tubular net is fitted over the bulk article.

20. A method according to claim 16, wherein said joining step comprises heating said portions of said strings. 

1. A wrapping apparatus comprising: first means for retaining a tubular net made of thermoplastic synthetic resin strings in a tubular shape, second means for gathering the strings at the edge of a first opening of the tubular net retained on the first means toward the longitudinal axis of the tubular net, tHird means for joining together the strings gathered by the second means by heating, and fourth means for fitting the resulting tubular net over an article to be wrapped from its second opening.
 2. The apparatus as set forth in claim 1 further comprising fifth means for feeding an elongated flatly folded rolled-up tubular net to the first means, a cutter means for severing the long tubular net approximately at definite spacing longitudinally thereof.
 3. The apparatus as set forth in claim 2 further comprising sixth means for forming second folds in the long tubular net at a position different from that of its first folds but in parallel to the first folds so as to shape the net into a tubular form.
 4. The apparatus as set forth in claim 3 wherein the sixth means comprises two pairs of pinch rolls spaced apart from each other along a linear path for feeding the long tubular net, the axes of one pair of the pinch rolls being approximately at right angles with the axes of the other pair of the pinch rolls, the axes of the pairs of pinch rolls being approximately at right angles with the linear feeding path.
 5. The apparatus as set forth in claim 4 further comprising a ball positioned in the long tubular net at the position between the pairs of pinch rolls.
 6. The apparatus as set forth in claim 1 wherein the first means comprises a cylinder and a core member to be inserted into and retracted from the inner space of the cylinder, the cylinder provides an internal annular space around the core member when the core member is inserted therein, the annular space being in a breadth approximately equal to the thickness of the strings, and the tubular net when positioned in the annular space is held by the cylinder and the core member, with at least the strings at the edge of the first opening of the tubular net projecting outward from the annular space.
 7. The apparatus as set forth in claim 6 wherein after the core member is retracted from the inner space of the cylinder, the tubular net remain on the core member.
 8. The apparatus as set forth in claim 6 wherein after the core member is retracted from the inner space of the cylinder, the tubular net remain in the cylinder.
 9. The apparatus as set forth in claim 6 wherein the core member has a conical portion permitting the strings to project outward thereover and tapered toward its top having a planar top face, the second means presses the projecting strings against the conical portion of the core member to gather the same, and the third means has a heating face to be pressed against the conical face and the planar top face of the conical portion.
 10. The apparatus as set forth in claim 9 wherein the operation to sever the folded long tubular net approximately at definite spacing and to cause the cylinder and the core member to retain the severed tubular net, the operation to gather the strings at the edge of first opening of the retained tubular net and to join the strings together and the operation to push out the tubular set having the joined strings from the cylinder and to fit the same over the article to be wrapped is automatically conducted as a plurality of sets of the cylinders and the core members arranged along a path of recyclic travel is drawn intermittently along the path.
 11. The apparatus as set forth in claim 10 wherein the plurality of sets of the cylinders and the core members is driven intermittently as one group and all the sets in one group perform the same operations substantially at the same time.
 12. The apparatus as set forth in claim 6 wherein the inner wall face of the cylinder is a conical surface and the outer wall face of the core member is a cylindrical surface, the internal space of the cylinder having reducing diameter toward its end from which the core member is inserted into the cylinder.
 13. The apparatus as set forth in claim 6 wherein the cylinder has a conical surface flaring toward its edges proximate to the edge of second opening of the tUbular net to be retained, the apparatus further comprising means for pressing the strings at the edge of second opening of the retained tubular net against the conical surface of the cylinder so as to diametrically expand the second opening, the fourth means being adapted to cause the tubular net having the strings joined at its first opening and the expanded second opening to be pushed out from the cylinder after the core member has been retracted therefrom and to be fitted over the article from the expanded second opening.
 14. The apparatus as set forth in claim 6 wherein the core member is provided with a position adjusting member for causing the retained tubular net to be projected to a substantially uniform level.
 15. The apparatus as set forth in claim 1 wherein the third means comprises a member for heating the strings and a heater for heating the member, the heater being adapted to heat the member when the member is away from the strings, the member having a heat capacity set at a minimum level required to join the strings of approximately one tubular net.
 16. A wrapping method for wrapping at least one bulk article of give minimum diameter comprising the steps of: a. supplying a tubular net of predetermined length, having first and second open ends and made of thermoplastic synthetic resin strips; b. supporting said tubular net by circumscribing said tubular net on a supporting means; c. gathering portions of said strings of the thus supported said tubular net toward a longitudinal axis of said tubular net, said portions being adjacent said first open end; d. joining together said portions of said strings to shape a small opening defined by said joined strips, the diameter of said small opening being smaller than said minimum diameter of the bulk article. e. removing said tubular net from the supporting means; and f. fitting the thus modified said tubular net over the one or more bulk articles to be wrapped by passing one or more bulk articles into said tubular net via said second opening.
 17. A method according to claim 16, further including as preliminary steps, the steps of supplying a long tubular net flatly folded and rolled up to a severing means, and severing said long tubular net to provide at least one said tubular net of predetermined length.
 18. A method according to claim 17, including the step of forming a plurality of folds in said long tubular net before the severing step, said folds being substantially parallel to each other.
 19. A method according to claim 16, including the step of diametrically expanding said tubular net before said tubular net is fitted over the bulk article.
 20. A method according to claim 16, wherein said joining step comprises heating said portions of said strings. 